We gather a lot of knowledge through our physical experiences in the world: what a good steak tastes like, how to get from home to work, or how it feels to be caught in a downpour. But at the same time, many of the topics that are most central to our lives, like the concepts of love, justice, or time, aren’t things we can directly experience, for example by seeing, touching, or tasting them. How, then, do we make sense of them?

One way we develop these concepts in our minds is by thinking about them in terms of concepts we do have direct experiences with. We use metaphors like love is a journey to conceptualize love in terms of a more concrete idea, a journey. Research I conducted with my advisor Lera Boroditsky shows that linguistic metaphors can actually cause us to think about concepts like time in new ways.

In our lab, we taught participants new ways of talking about time that used vertical terms to talk about sequences of events. For example, some people learned that earlier events take place above later ones. They were told things like Tuesday is higher than Wednesday, and When we eat dinner, breakfast is above us. Other people learned the opposite system of metaphors, that earlier events take place below later ones.

After learning these metaphors, participants completed a task that measures how much they subconsciously associate different parts of space with different aspects of time. This task didn’t require language to complete it (people saw pictures and pressed buttons to indicate the order that events happened in), so there was no encouragement for people to even connect this task with the earlier part of the experiment in which they learned new ways to talk about time.

We found that people associated space with time in ways that were consistent with the new metaphors they had just learned. Those who learned that earlier events happen above later ones tended to associate earlier events with higher space than later events and vice versa.

Learning a new way to talk about time creates new ways of thinking about it.

This work is based on a foundation of research pointing to similarities between the way we talk and think about time. Across languages, people often use spatial language to talk about time. For example in English, we can have a long meeting or time can fly by, we look forward to the future and back on the past, and it’s appropriate to say either that we’re approaching a deadline or that the deadline is approaching us. In all of these cases, the metaphors we use to talk about time suggest that passage of time is akin to movement through space.

Using space to talk about time is not specific to English. Many languages include similar metaphors, though different aspects of space can be associated with different aspects of time. For example, the Aymara, a group in South America, refer to the past as ahead of them and the future as behind, a reversal of the English convention. Similarly, speakers of Mandarin Chinese can use vertical language — the same words that mean up and down — when talking about time.

We don’t just use spatial language to talk about time, but we actually think about time in ways that are consistent with the specific spatial metaphors our language uses. For example, English speakers lean slightly forward when thinking about the future and back when thinking about the past, and demonstrate subconscious associations between space in front of the body and the future and space behind the body and the past on reaction time tasks. These studies suggest that we’re often drawing on our knowledge of space when we think about time.

Does the language we use to talk about time (like the future ahead of us and past behind) cause us to actually think of time in consistent ways, or do we use these spatial metaphors because we naturally think about the future in front of us and the past behind? This is pretty much a textbook chicken-and-egg problem.

Both possibilities could be true, but existing research can’t shed light on causal relationships. Showing that Mandarin speakers think about time vertically (consistent with their metaphors in language) and English speakers do not doesn’t tell us that different metaphors cause differences in thought — there are many ways in which two groups of people who speak different languages will differ, and it’s impossible to know whether any of those factors actually lead to an observed difference in thinking about time between the two groups. In order to make the causal claim — to know whether metaphors in language can actually shape the way people think about time — we needed to randomly assign participants to conditions. By teaching all participants a new way of talking in the lab, that’s exactly what we did — we randomly assigned some to the group that learned that earlier events are above later ones and others to the group that learned that earlier events are below. This way we could be sure that the metaphors participants learned, and not some other uncontrolled difference between the two groups, was the reason the two groups differed in the way they associated vertical space and time.

This work shows that metaphors in language can shape the way people think. In fact, learning a new way of talking about time can foster new ways of thinking about this topic that is central to our everyday lives.